Never got a positive opk

Rolita
Hello ladies, I been testing with doller tree opk right after AF, I been testing twice a day sometimes 3 or 4 on the days I assumed ovulation and I didn't get any positive tests just a fade in and now a fade out pattern where the test line got dark but never as dark as the control line, what do you all think? Did I ovulate? R the tests wrong? Is it possible to have regular cycles and have a clockwork AF but not ovulate?